The present invention relates to an apparatus for forming cells in continuous strips, particularly for packaging suppositories and the like.
As is known, products such as suppositories, pessaries and the like are currently packaged by using two films made of thermoformable synthetic material which are coupled and in which containment cells, which reproduce the shape of the suppositories or pessaries, are defined. The cells initially have an open neck inside which the substance which composes the suppositories or pessaries is injected; said substance, by hardening, assumes the shape of the cells. The neck for the insertion of the substance is sealed after filling.
The methods currently used to manufacture said containers entail the coupling of two films made of synthetic material, welding them in preset regions so as to define mutually spaced cells along the extension of the films. Usually, on films which extend in a continuous strip, cells which are opposite with respect to a longitudinal median region of the films, which is not affected by the welding and is transversely connected to the cells, are defined. The films are then heated and inserted in forming molds in which forming cavities are defined; said forming cavities have a shape which corresponds to the final shape of the cells to be obtained. Pressurized air is injected through the central region and reaches the cells, defined by means of the previously executed welding, causing their expansion and adhesion to the forming cavities.
The strip which is obtained at the end of the forming thus has two rows of opposite cells and an expanded longitudinal median region which is connected, by means of ducts or necks, to the various cells.
Depending on whether the filling machines for which said strips are intended require or not a certain rigidity of the strips, the strip with double row of cells is cut at its median line so as to obtain two strips in each of which half of said expanded region is present, or said expanded median region is removed completely so that the strip can be o coiled in rolls.
If the expanded median region is not discarded, each of the two strips obtained has, at a longitudinal edge, flaps which increase the flexural rigidity of the strip in its passage through the filling machines. After filling, the ducts for access to the cells are sealed and the flaps are removed by cutting.
In both of the above described processes there is a considerable waste of material which affects the manufacturing costs of said types of container.
In order to solve this problem, an apparatus, disclosed in the U.S. Pat. No. 1,197,898 in the name of the same Applicant, has been provided which permits to eliminate said waste of material, allowing to produce strips arising from the coupling of two synthetic films with cells and without flaps. Although said apparatus has a modest bulk and high reliability, it has the disadvantage that it is complicated to manufacture, with unavoidably high production costs.